Deformation of a deep excavation adjacent to metro tunnels in soft soils

The deep excavation of Shanghai Bund 596 Plot is adjacent to the metro tunnels of Line 9, pipelines and buildings. In order to control the impact of excavation construction on the metro tunnels, many measures are adopted in the design of the project. The deep excavation is divided into four small pits, and the block excavation method was adopted. Dual-purpose diaphragm walls are used as retaining walls. The steel struts with automatic axial force compensation system are adopted in the small pits just adjacent to the metro tunnels. The soils in the passive zone are reinforced by triaxial cement-soil mixing piles. The monitored results show that the maximum lateral displacement of the diaphragm walls far away from the tunnels and that just adjacent to the tunnels are 45.6 and 17.2 mm, respectively. The maximum upheaving of the tunnels is about 12.9 mm. The design scheme satisfies the requirements of deformation control of the adjacent tunnels.